Modern hybrid and electric vehicles utilize battery packs to provide energy for propulsion and for storing regenerated energy. Battery packs are typically composed of multiple individual battery cells that may be connected in parallel, series or some combination thereof. A characteristic of the battery pack is state of charge (SOC). The battery pack SOC is a measure of the fraction of the total charge that remains in the battery pack and may be considered analogous to a fuel gauge. SOC may be important for determining when and how to charge or discharge the battery pack. SOC may also be important for providing information to the driver, such as vehicle drive range, and for operating the vehicle.